Electric spark-plug.



F. R. BLAKE.

ELEGTRIG SPARK PLUG.

APPLIOATION FILED mmm, 1912.

Patented Feb. 18, 1913.

www c/ l Loaaavo.

entran sra'rns earner cierren.

FRANK R.' BLAKE, 0F EIALDEN, MASSACHUSETTS, ASSIGNOR TO BLAKE SPARK PLUG GG., F VBfJSCi'JIi',A MASSACHUSETTS, A CORPORATION 0F MASSACHUSETTS.

ELECTRIC SPARK-PLUG.

To ful 'whom t may concern Be itl linown that I, FRANK It. BLAKEt a citizen of the United States, residing at Malden, in the countyof 'Middlesex and State of Massachusetts`,`have invented new and useful Improvements in Electric Spark- Plugs, of which the following is a speciication.

The'present invention provides a spark plug for explosive engines which will 'admit ot access being readily had to the electrodes for cleaning, replacement, adjustn'ientor other cause and which involves a simple and` economical structure.

The invention consists of the novel teatures, details ot Construction and combination of parts, which hereinafter will be more particularly set forth, illustrated in the'accompanying drawing, and pointed out in the appended claims.

Referring to the drawing(` forming a part of the specification, Figure 1 is a. sectional view of an electric spark plug embodying the inventipn. Fig. 2 is a sectional view of the metal sleeve insulating core and central electrode. Fig. 3 is a sectional view of the shell.

Corresponding and like parts are referred to in the following description, and indicated in all the views of the drawing, by the. same reference characters.

The cent-ral electrode comprises a slender body 1 having-a head 2 at its inner end and a point 3. A core 4 of insulating material receives the electrode 1, said core tapering throughout its length and having a central opening in which the electrode is `fitted. A. recess 5 is formed at the inner enlarged end of the insulating core and receives the head 2 and point 3 of the central'electrode. The insulating core ima-y be formed of any material and preferably consists of a tape or ribbon of insulating material wound upon itself and having the windings overlapped.`

A metal sleeve 6 has a' centrally disposed tapered opening to snugly receive the core 4; and is provided at its inner end with oppositely disposed lugs 7 and at its outer end with a flange 8 and projection 9, which forms a handle or finger piece to admit oi? turning the sleeve to secure or release the same from the supporting shell V10. A washer 11 of insulating material is slipped upon the projecting end of the core LPand is confined between the outer end of the j j vspecification@metiersraient.. Patent-eenen.ienne. applicati@ ned January 24, 1912. seriarno. 673,049. i

sleeve 6 and a nut 1Q, the latter being threaded upon the projecting end of the electrode 1. The washer 11 may be of any insulatingmaterial and provides a grip or handle for manipulating the sleeve 6 when placing the 'same or removing it from the shell 10. An

electrode 13 is had atI the inner end of the sleeve 6 and curves around the inner end of the core 4 and approaches closel to the point il so as to provide the proper'spark gap.

The shell 10 is provided at its inner end with a reduced part 14, which is externally threadedto make screw connection with the head of the engine cylinder in the usual manner. The opening through the shell 10 tapers slightly to conform to the taper of the sleeve 6. The shell 10 has grooves 15 at opposite points in the wall of the open ing through which 'the lugs 7 of the sleeve 6 are adapted to pass. After the lugs 7 clear the inner end of the shell the sleeve 6 is given a partial turn to throw the lugs 7 out ot register with the grooves 15 and to cause them to engage the inner edge of the Shelhthereby maintaining the sleeve 6 in position. It dllows that when required the sleeve 6 and. parts attached thereto may be readily removed from the shell 10 or quickly placed in position therein. When it is required to remove the sleeve 6 the same is given a partial turn to bring the lugs 7 in line with the grooves 15 when the sleeve G may be withdrawn `from the shell.

From the foregoing description, taken in 'connection with the accompanying drawing,

the advantages of the construction and of the method of operation will be readily apparent to those skilled in the art to which the invention appertains, and while I have described the principle of operation ot the invention, together with the device which I now consider to be the embodiment thereof, I desire to-have it understood that the device shown is merely illustrative, and that such changes may be made when desired as are within the scope of the claims appended hereto.

Having thus described the invention what is claimed as new, is j l. 1. In Aan electric spark plug for explosive engines, a metal shell having a tapere opening and provided with longitudinal grooves in the walls of the tapered opening at the inner end thereof, a tapered metal sleeve removably fitted within said metal shell and having an outer flange and a projecting handle at its larger end and provided With o'standing lugs at its smaller end to pass through the longitudinal grooves of the lmetal shell and engage the inner end thereof upon giving the sleeve a partial turn to secure it within the shell, a core of insulating material tittedwithin said sleeve, an electrode inserted in the core of insulating niaterial, and a second electrode having connection with the metal sleeve.

2. In an eleerie spark yplug for explosive engines, a nieta shell having a tapered opening and. provided With longitudinal grooves in the Walls of the tapered opening at the inner end thereof, a tapered metal sleeve removably fitted within said metal. shell and having an outer flange and a projecting handle at its larger end and provided with offstanding lugs at its smaller end to pass through the longitudinal grooves of the metal shell and engage the inner end thereof .upon giving the sleeve a partial turn to secure it Within the shell, said tapered sleeve having an electrode at its smaller end,a

, Copesvo this patent mayv he obtained for tapered core of insulating material fitted Within the said sleeve and projecting beyond the ends thereof and having a recess at its inner or larger end, an electrode fitted Within the tapered core and having a head at its inner end to engage the inner end of the recess thereof, said electrode being further provided With a point extending into the sa id recess and approaching close to the electrode of the before mentioned sleeve to provide a `proper spark gap, said electrode projecting beyond the core' and having its end threaded, a Washer of insulating material slipped upon the outer end of the core MAY S. BLAKE, ABBIE MEARS.

ive cents each, by addressing .the Commissioner of Patents, Washington, D. C. 

